This invention relates to dynamoelectric machines and more particularly, to an electric motor whose stator and rotor assemblies are insulated from electrical contact with outside objects so that the motor does not require additional electrical grounding prior to use.
Conventional dynamoelectric machines, such as electric motors, are fabricated by assembling various stator and rotor elements. Generally the stator and rotor assemblies are placed in a metal housing or shell closed by endshields. In the past, various construction techniques have been employed for constructing motors used in domestic appliances, for example dishwashers and washing machines. In the attempt to lower production costs, glue together motor constructions have proved successful over the years. These techniques, however, do not easily lend themselves to automated motor production. For example, shims are usually required during assembly of the various stator and rotor components to ensure a uniform air gap is provided for motor operation. This is particularly disadvantageous because the insertion and removal of the shims are done by hand.
In addition, appliance motors generally require an external ground wire or ground lead so the motor can be grounded in applicational use. The ground attachment generally is made after the motor is mounted or attached to another metal structure in the appliance. The mating surface of that structure also must be machined so that the motor can be properly attached in applicational use. This can be a time consuming operation, particularly where the motor is being assembled to the structure as part of an ongoing manufacturing operation.
The invention disclosed hereinafter decreases these prior art difficulties with a construction that is low in cost and easily automated. Constructional details are contained in copending U.S. Patent Application Ser. Nos. 07/255,756 by Baker, 07/255,755 by Borcherding, 07/255,758 by Borcherding et al, 07/255,707 by Ottersbach, 07/255,727 by Hildebrandt et al, 07/255,706 by Borcherding et al, and 07/255,838 by Borcherding, which are assigned to the assignee of the present application, the disclosures of which are intended to be incorporated herein by reference.